If you have the Contrib CD, there is a nice mixer called rexima on it. Look for rexima.tgz. It uses arrow keys to adjust settings and also can take command line arguments. For example "rexima -mic 80" will crank up the output on your microphone as by default, it is near 0. It's a good thing to get some settings you like and put the command to set them in /etc/rc.d/rc.local. Hope that helps.
